Of the many theories that have emerged over the last 15 years as to who was behind the drive-by killings of Tupac Shakur and Biggie Smalls, the closest thing we've seen to an investigative end is ex-LAPD Detective Greg Kading's Murder Rap.

The book details the former cop's three-year stint as head of a Biggie Smalls task force formed by the LAPD's Robbery-Homicide Division. Throughout the tumultuous investigation from May 2006 to July 2009, many of his leads hit a wall -- but by the end, a couple key informants positioned Kading to solve the Shakur/Smalls murder mystery.

Here, in the most digestible form possible, are the players and events that have led to Kading's latest revelations. Because we know what a convoluted mess this case, shrouded in the obsession and paranoia of an invested few, has become for the casual observer.

Tupac Shakur: Once the rising star of Death Row Records, the West Coast's biggest gangsta-rap label in the 1990s. Shot and mugged at New York's Quad Studios in 1994. Murdered in a Las Vegas drive-by two years later.

Christopher Wallace, aka Biggie Smalls, aka The Notorious B.I.G.: The East Coast's lovable, 400-pound answer to the gangsta-rap boom. Hardest, steadiest flow ever borne off the streets of Brooklyn. Killed at the height of his mid-'90s rise to fame, just six months after Shakur.

Suge Knight and Tupac Shakur (forefront) in Vegas, minutes before the fatal shooting.

Suge Knight: Head of L.A.'s now-defunct Death Row Records. Known for his violent streak and imposing, 6-foot-four-inch frame. Friend of the Bloods.

Sean Combs: CEO of Bad Boy Entertainment. Watched Smalls, his biggest earner and best friend, die in front of his eyes after the 1997 drive-by. Since then, Combs has expanded the Bad Boy name into the film, apparel and restaurant industries. He's estimated to be worth nearly $500 million, and is very litigious when it comes to accusations surrounding the Shakur shooting. Friend of the Crips.

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Theresa Swann: Alias used in Murder Rap for one of Knight's baby mommas. She claims Knight gave her the money to hire a hitman to kill Smalls, and thus avenge the murder of Shakur months before.

Wardell "Poochie" Fouse: A close associate of Knight's. A couple prison sources in Murder Rap point to him as the guy Knight may have commissioned to carry out the crime against his East Coast rivals. Swann confirms this theory in her confession to Kading and the task force.

Duane Keith "Keffe D" Davis: A Southside Crips shot caller who tells Kading he was in the passenger's seat of the Caddy used to pop Shakur. He says Combs offered him $1 million to take out both the rapper and his manager (Knight), The latter would come out alive with a bullet wound to the head.

Orlando "Baby Lane" Anderson: Keffe D's nephew. The target of an infamous assault at MGM Grand the night Shakur died (see below). Las Vegas police wrote in their report that the beatdown was revenge for the theft of a Death Row medallion Baby Lane had stolen months before. In his confession, Keffe D claims his nephew was the one who pulled the trigger on Shakur. Baby Lane was eventually shot dead himself in a 1998 gang confrontation over drug money.

Ex-LAPD Detective Russell Poole: Took over as lead Robbery-Homicide detective on the Smalls shooting, one month into the Wilshire Division's investigation. First to suggest that wayward LAPD cops answering to Knight had participated in the murder. Frustrated that top brass seemed to be hampering his probe into LAPD's own, Poole retired in protest circa 1999 and sued the department for "violating his First Amendment rights by preventing him from going public with his investigation."

Ex-LAPD Officer David Mack: Rogue LAPD officer whom Detective Poole believed played a central role in the Smalls murder. Drove the same model of Impala used in the shooting, and kept a Shakur "shrine" in his home, according to investigators. Jailed after he committed a large-scale bank heist in South L.A., just months after Smalls was shot dead.

Ex-LAPD Officer Rafael Perez: Mack's close friend on the force, and another of the cops implicated by Poole.

Amir Muhammed, aka Harry Billups: A friend of Mack's from college. Poole's key suspect as the triggerman who blasted Smalls -- although Kading spends a few pages of Murder Rap refuting that theory.

Voletta Wallace: Smalls' mother, a cool Jamaican lady dedicated to finding her son's killer(s). Filed a civil lawsuit against the City of Los Angeles in 2002, alleging police involvement. (The suit was later assigned a crushing $500 million price tag.) She didn't drop the charges until 2010, after being promised that the LAPD's criminal investigation into Smalls' death was being reinvigorated.

Perry Sanders: Wallace's lawyer. After reading Murder Rap, Sanders tells the Weekly he's still unconvinced by Kading's detective work disproving the "rogue cop" theory, as well as Swann's confession. Sanders thinks the woman's story doesn't stand up because she alleges Knight knew Smalls would be at the Peterson Automotive Museum the night of the hit. In fact, the lawyer says, Smalls was supposed to be out of the country, and his appearance at the party was a fluke. (Kading maintains that Knight never would have known the Bad Boy Entertainment star was planning to skip one of the biggest industry bashes of the year.)

Judge Florence-Marie Cooper: The federal judge assigned to Wallace's suit. Sided very vocally with the plaintiffs, but the closest she could come to a positive ruling was the mistrial she declared in 2005, upon learning that LAPD internal affairs had raided department desks for anything relating to Mack and stowed it away. Strangely, Cooper died from a stroke in early 2010. Many have speculated that her departure contributed to Wallace's April 2010 decision to withdraw her lawsuit against the city.

Randall Sullivan: Non-fiction writer who popularized Poole's conspiracy theory with a widely read book and Rolling Stone piece detailing every suspicious link between the LAPD, Death Row Records and the tragic shooting that took Smalls' life.

Chuck Philips' career was ruined by the cursed Shakur-Smalls mystery.

Dennis Romero

Chuck Philips: The Los Angeles Times reporter who claimed to have solved the Shakur murder in 2002. The paper sourced anonymous gang members saying Smalls had paid the Southside Crips $1 million to get rid of Shakur. (That article was never retracted, despite cries of protest from Voletta Wallace.) Philips' next big piece on the deadly feud, however -- focusing on Shakur's bloody mugging in 1994 -- was withdrawn after a crime blogger discovered the story had relied on FBI court documents faked by a crazy con artist/wannabe inside man. The Times issued a front-page retraction for the piece, apologizing specifically to Combs for implicating him in the shooting. Philips was immediately let go by the paper, despite his claims (to this day) that the story still has legs without the FBI documents, and that his editors forced him to use the faked papers to strengthen his already sound investigation.

James "Jimmy Henchman" Rosemond: Combs' old business partner and current Interscope mogul, also implicated as an orchestrator of the 1994 Shakur mugging in the retracted Times article. Recently the target of a Brooklyn prisoner's confession that Rosemond hired him to carry out the attack. Nabbed this year by FBI agents for allegedly running a cross-country cocaine ring.

Ex-LAPD Chief Bernard Parks: Head of the LAPD during both Poole's frenzy of accusations and the larger Rampart Scandal that fanned the flames.

Ex-Robbery-Homicide Division Captain Kevin McClure: Oversaw the dismantling of the Smalls/Shakur murder investigation in 2010. Sticks by his decision today, saying, "I had to prioritize -- and it's not like I had unlimited resources."

Ex-LAPD Chief William Bratton: Head of the department when Kading was pulled off the task force. Kading's commander told him the decision had come from above, because the department didn't want negative scrutiny applied to the Smalls investigation. (At the time, Kading was the target of an LAPD internal affairs review of his work on another case. A year later, he was cleared of those accusations. But it was too late: The Smalls investigation had been shelved once again.) Bratton's reign was famously feel-good, with very little negative press.

LAPD Chief Charlie Beck: Current LAPD boss. Under Beck, the search for Shakur and Smalls killers was called off. Today, the media relations office says Beck cannot comment on the investigation, but that "this is an active/ongoing case still being investigated by our detectives." If true, this means the case would have had to have been reopened in the four or five months since McClure left Robbery-Homicide.